Not Applicable
1. Field of Invention
This invention pertains to adapters for fiber optic cables. More particularly, this invention pertains to a fiber optic adapter which is removable from a receptor attached to a box.
2. Description of the Related Art
Optical fibers are commonly used for the transmission of all types of data, including telecommunications, video, and computer data. Unlike copper cables which use mechanical connections to terminate to equipment, fiber optic cables rely upon optical connectors for termination.
An optical connector consists of a ferrule, through which the optical fiber is fed. The distal end of the ferrule and fiber combination is polished to a precise endface geometry. The ferrule and fiber endface is butted to another fiber optic cable""s ferrule and fiber endface, bringing the fiber endfaces into precise physical contact. In order to minimize signal loss, the fiber and ferrule endfaces must have a very smooth and clean surface. Cleanliness of the fiber and ferrule endface is critical to the good performance of fiber optic connectors. Recently, awareness and concern about connector cleanliness has grown dramatically due to a number of factors, including the value of traffic, the growth of bandwidth, the growth of mechanical connector use, and network sensitivity.
Considering the small size of fiber cores (9 microns for a single mode fiber), it is easy to understand how contaminants such as dirt or oil can affect the performance of fiber-optic connectors. The polished surfaces can be scratched when the connectors are repeatedly mated, if the optical fibers rotate after they come in contact, or if a foreign particle is on one of the connector end faces. Also, the connectors and associated hardware are constructed of materials which are rich in hydrocarbons and materials which tend to outgas and create relatively large partial pressures of these materials. The space wherein the fibers and connectors mate is so small that it can be considered a capillary space. As a result, these gaseous products tend to xe2x80x9cwickxe2x80x9d into the space and deposit. For these reasons, it is now understood that the polished optical surfaces must be protected from physical damage and contamination and must be periodically cleaned.
Fiber optic connectors are commonly available in various sizes and configurations. Commercially available connector types include SC, LC, FC, ST, MT-RJ, SMA, MU, LX.5, and E2000, among others. It is important to note that all connectors must be mated in an adapter, which consists of a housing geometry suitable to the connector type and a xe2x80x9cfloatingxe2x80x9d split sleeve that accepts and aligns the connectors for precise mating of the small fiber cores used for single mode fiber. The molded glass-filled thermoplastic alignment sleeves commonly used can also be a source of contamination because the ferrules scrape the material of the sleeve each time the connectors are mated.
It is common to fit the adapter with locking means which permit the easy insertion of the adapter into a receiving aperture in a box. Typically, spring clips are used. These spring clips are pushed against the adapter body when the adapter is inserted into the aperture. When the adapter is fully inserted, the spring clips return to an extended position, preventing the adapter from being pulled out of the aperture. Accordingly, the adapter cannot be removed without access to the inside of the box.
Often, the adapter defines the interface between an outside box connector and an inside box connector. Normally, only the connector on the outside is accessible for cleaning, while the connector on the inside is inaccessible without opening the box. In most cases the manufacturer of the box prohibits opening the box because of the potential for damaging sensitive and critical internal components, among other reasons. Therefore, it would be beneficial to be able to remove the adapter and remove the inside connector from the adapter without opening the box. After cleaning, it would be beneficial to be able to replace the inside connector and the adapter without opening the box. Furthermore, fiber optic cable has very strict bend radius requirements and it would be beneficial if the adapter were positioned on the box such that cable bends are minimized.
Therefore, it is an object of the present invention to provide a means for removing an adapter from a box after the adapter has been secured to the box.
It is a further object of the present invention to be able to remove and replace the adapter without entry into the box.
It is a still further object of the present invention to remove and replace the adapter from the box without resort to tools or other devices.
Another object of the present invention is to provide a means for mounting the adapter to the box such that the fiber optic cable exits the adapter in the general direction of the cable routing.
Other objects and advantages over the prior art will become apparent to those skilled in the art upon reading the detailed description together with the drawings as described as follows.
According to an embodiment of the present invention, a removable adapter and a receptor is disclosed, whereby the adapter is releasably secured in the receptor. The adapter has an adapter flange bisecting the adapter body. The receptor or mounting plate, which is attached to a box face, has a first aperture or through-opening penetrating its front surface and a second aperture or slot in the same plane as the front surface but disposed between the front surface and the back surface of the plate. The second aperture intersects the through-opening. The through-opening has a seating lip or shoulder which protrudes into the through-opening adjacent to the back surface of the mounting plate. The adapter is inserted into the through-opening and rotated such that the adapter flange is lockably disposed in the second aperture. The means for locking include the use of detents which lockably engage recesses and the use of a tapered slot, by which the adapter flange is wedged in the slot when the adapter is rotated.
An alternative embodiment of the receptor includes forming the receptor such that its front surface and its mounting surface are not parallel, but instead, the planes formed by the two surfaces intersect, resulting in the receptor having a wedge shape. In this embodiment, after the adapter is lockably disposed in the second aperture, the adapter""s long axis is not perpendicular to the box face on which the receptor is disposed, but is at an approximately 22 degree angle to a line perpendicular to the box face. This angle serves to reduce bending of the fiber optic cable as it is routed away from the adapter.
Another embodiment of the present invention includes a receptor, which is attached to a box face, and a removable adapter plate, which has means for receiving a standard adapter. The receptor has a round through-opening which has opposing notches. The removable adapter plate has a cylindrical body with two tabs. The through-opening in the receptor receives the removable adapter plate, with the tabs passing through the notches and being disposed on the posterior of the receptor. The removable adapter plate has a shoulder which rests on the anterior of the receptor and prevents the adapter plate from passing completely through the through-opening in the receptor. After the removable adapter plate is inserted into the through-opening in the receptor, the removable adapter plate is rotated and locked in place. The means for locking include the use of detents which lockably engage recesses and the use of a tapered thickness of the receptor, by which the receptor is wedged between the tabs and the shoulder when the removable adapter plate is rotated. The removable adapter plate has a through-opening into which the adapter can be inserted and locked in place.